Published online before print February 23, 2009
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,1
* Departments of Gastroenterology and
Immunology, Hospital Clínic, IDIBAPS, and
Department of Experimental Pathology, Institut dInvestigaciones Biomèdiques de Barcelona (IIBB)-Consejo Superior de Investigaciones Científicas, CIBER-EHD, Barcelona, Spain
1 Correspondence: Department of Experimental Pathology, Institut dInvestigaciones Biomèdiques de Barcelona (IIBB)-CSIC, Rosselló 161, Barcelona 08036, Spain. E-mail: azsbam{at}iibb.csic.es
ABSTRACT
Loss of tolerance toward commensal bacteria has been invoked as a mechanism for Crohns disease. IL-10 is a key anti-inflammatory cytokine that plays a role in induction and maintenance of tolerance. The aim of this study is to determine IL-10 production in response to bacterial components in Crohns disease patients, who were classified according to their phenotypes as stricturing, penetrating, or inflammatory. Peripheral blood was obtained from Crohns disease patients and healthy controls. Cytokine production was measured in whole blood cultures, isolated CD4+ cells, and monocyte-derived dendritic cells (MDDCs). Under unstimulated conditions, IL-10, but not IL-12, was down-regulated significantly in blood cultures of patients with severe phenotypes, compared with inflammatory, nonpenetrating, nonstricturing Crohns disease patients. In response to LPS, IL-10 was up-regulated more significantly in patients with no fistulae or fibrosis. Study of IL-10 production by isolated cell subsets showed that DCs, but not CD4+ T cells, from penetrating Crohns disease produced significantly less IL-10 in response to LPS. Differences were not associated with the 1082A/G polymorphism in the IL-10 gene promoter. We show a defect in IL-10 production in whole blood cell cultures and MDDCs in patients with severe forms of Crohns disease. This defect in IL-10 production by a group of Crohns disease patients may represent a mechanism mediating more severe manifestations of the disease. We propose that treatment with IL-10 or IL-10-inducing therapies could be of particular benefit to these group of patients.
Key Words: dendritic cell IL-12 dendritic cell LPS